An estimated 4 to 5 million Americans (about 2% of all ages and 15% of those older than age 65) have some form and degree of cognitive failure. Cognitive failure (dysfunction or loss of cognitive functions, the process by which knowledge is acquired, retained and used) commonly occurs in association with central nervous system (CNS) disorders or conditions, including age-associated memory impairment, delirium (sometimes called acute confusional state), dementia (sometimes classified as Alzheimer's or non-Alzheimer's type), Alzheimer's disease, Parkinson's disease, Huntington's disease (chorea), cerebrovascular disease (e.g., stroke, ischemia), affective disorders (e.g., depression), psychotic disorders (e.g., schizophrenia, autism (Kanner's Syndrome)), neurotic disorders (e.g., anxiety, obsessive-compulsive disorder), attention deficit disorder (ADD), subdural hematoma, normal-pressure hydrocephalus, brain tumor, head or brain trauma.
Cognitive dysfunction is typically manifested by one or more cognitive deficits, which include memory impairment (impaired ability to learn new information or to recall previously learned information), aphasia (language/speech disturbance), apraxia (impaired ability to carry out motor activities despite intact motor function), agnosia (failure to recognize or identify objects despite intact sensory function), disturbance in executive functioning (i.e., planning, organizing, sequencing, abstracting).
Cognitive dysfunction causes significant impairment of social and/or occupational functioning, which can interfere with the ability of an individual to perform activities of daily living and greatly impact the autonomy and quality of life of the individual. Thus, there is considerable interest in identifying clinical candidates for use in rehabilitating an animal with any form of cognitive dysfunction.